{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "class Solution(object):\n",
    "    def titleToNumber(self, s):\n",
    "        \"\"\"\n",
    "        :type s: str\n",
    "        :rtype: int\n",
    "        \"\"\"\n",
    "        # Make a set of char-num pairs\n",
    "        conv = {}\n",
    "        cnt = 0\n",
    "        for w in range(ord('A'), ord('Z') + 1):\n",
    "            conv[chr(w)] = cnt\n",
    "            cnt = cnt + 1            \n",
    "        \n",
    "        w = 1\n",
    "        num = 0\n",
    "        while s:\n",
    "            num = num + (conv[s[-1]]+1) * w\n",
    "            w = w * 26\n",
    "            s = s[0:-1]\n",
    "        return num"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [],
   "source": [
    "s = Solution()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "701"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s.titleToNumber('ZY')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.6.3"
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 "nbformat": 4,
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